Newer designs and manufacturing techniques have driven electronic components to small dimensions and miniaturized many communication devices and systems. Unfortunately, antennas have sizes that are related to wavelength, and they have not been reduced in size at a commensurate level and they increasingly are one of the largest components used in small communications devices. In Ultra High Frequency and lower communication applications, antennas size becomes increasingly larger. At very low frequencies, for example, used by submarines or other low frequency communication systems, the antennas become very large, which is unacceptable. It becomes increasingly important in these communication applications to reduce not only antenna size, but also to design and manufacture a reduced size antenna having the greatest gain for the smallest size.
In current, everyday communications devices, many different types of patch antennas, loaded whips, copper springs (coils and pancakes) and dipoles are used in a variety of different ways. These antennas, however, are sometimes large and impractical for a specific application.
For years, some antenna designers used Maxwell and Wheeler antenna design theories, and concentrated on using spherical shapes with many loops of coil. These prior art designs were typically based on Maxwell's spherical inductor with a forced resonance using capacitors. An example of such prior art antenna is a three dimensional inductor loop antenna. Other antenna designs stressing a small size have used one-half silver wire dipole, but have been limited to full size, self resonant antenna structures. Two-dimensional antenna designs as inductor/loop antennas have been designed as silver annular rings, but were not practical even though some were small.
Other prior art antenna designers have tried to improve Maxwell's spherical inductor and Wheeler's coil, with forced resonance or variable impedance devices, while maintaining a small antenna design. For example, in the beginning days of radio, the earliest variable ratio transformers used a secondary, larger winding and a mechanism that used another primary winding located inside the larger winding. With this design, the fields aided or opposed each other. In other research and development laboratories, it was believed that the best way to make these and other types of spherical antennas resonant was to add greater turns of wire. Unfortunately, as the turns of wire increased, the additional windings “shaded” the antenna aperture against adjacent turns of the wires and interrupted the field. The cost and operational efficiency of this antenna was reduced. Many of these antennas also did not have a uniform current distribution and had Eddy currents distributed throughout the antenna. Also, with many windings, these prior art spherical antenna had a proximity effect and flux escaped.
Some define this invention to be the smallest possible antenna, as it provides the greatest gain and efficiency in the shortest length, by virtue of a spherical geometry, which provides the greatest surface area for the smallest volume.